scholarly journals Protonation site for anilines in aqueous media

2002 ◽  
Vol 67 (2) ◽  
pp. 111-113 ◽  
Author(s):  
Alexei Pankratov ◽  
Inna Uchaeva
Keyword(s):  
Nitrogen Atom ◽  
Aqueous Medium ◽  
Gaseous Phase ◽  
Aqueous Media ◽  
Aminobenzoic Acid ◽  
Amine Nitrogen Atom ◽  
Protonation Site ◽  
Amine Nitrogen ◽  
Aminobenzoic Acids ◽  
Phase Proceeds

By means of the PM3 method it has been shown that the protonation of 2-, 3 4-methoxyanilines, 4-methylthioaniline, 2-, 3-, 4-aminobenzoic acids, 2 3-, 4-nitroanilines in the gaseous phase proceeds via the amine nitrogen atom. The same result, attributed to the aqueous medium, was obtained for 4-methoxyaniline, 4-aminobenzoic acid and 4-nitroaniline.

N10-(2′-Mercaptoethanoyl)-2,2,5,5-tetramethyl-3,4-diathia-7,10-diaza-bicyclo[5.3.0]decane and its reaction with oxotrichlorobis(triphenylphosphine)rhenium(V)

1996 ◽  
Vol 74 (4) ◽  
pp. 574-582 ◽  
Author(s):  
H. Alarabi ◽  
R.A. Bell ◽  
H.E. Howard-Lock ◽  
J. Kowanetz ◽  
C.J.L. Lock
Keyword(s):  
Nitrogen Atom ◽  
Heavy Atom ◽  
Direct Methods ◽  
Ligand Molecule ◽  
Amine Nitrogen Atom ◽  
Rhenium Atom ◽  
Amine Nitrogen ◽  
Bond Lengths ◽  
X Ray Crystallography ◽  
Equivalent Distance

The ligand molecule N10-(2′-mercaptoethanoyl)-2,2,5,5-tetramethyl-3,4-dithia-7,10-diazabicyclo[5.3.0]decane has been prepared and characterized by 1H and 13C NMR spectroscopy and by mass spectrometry. The protected analogue, N10-[(2′-triphenylmethylthio)ethanoyl]2,2,5,5-tetramethyl-3,4-dithia-7,10-diazabicyclo[5.3.0]decane dimethanol hemihydrate, was examined by the same techniques and also by X-ray crystallography. Crystals were triclinic, P-1, a = 11.125(2), b = 11.986(2), c = 13.562(3) Å, α = 103.54(3)°, β = 90.29(3)°, γ = 107.11(3)°, and Z = 2. The crystal was unstable in air at room temperature, so measurements were made on a crystal sealed in a tube that contained methanol vapour Intensities were measured with a Rigaku AFC6R diffractometer and monochromated CuKα radiation (λ = 1.54178 Å). The structure was solved by direct methods and refined to R = 0.1497, wR = 0.0655 based on 5000 independent reflections. The high residuals were caused by solvent disorder. Bond lengths and angles were normal. The reaction of the ligand with oxotrichlorobis(triphenylphosphine)rhenium(V) yielded an unexpected asymmetric complex, oxo(1,1-dimethyl-1,8-dimercapto-3,6-diazaoctan-7-onato-N3,N6,S1,S8) rhenium(V). Crystals were monoclinic, P21/n, a = 10.633(2), b = 11.221(2), c = 11.678(1) Å, β = 116.10(1)°, Z = 4. Intensities were measured with a Siemens P4 diffractometer and monochromated MoKα radiation (λ = 0.71073 Å). The structure was solved by the heavy atom method and refined to R = 0.0471, wR = 0.0340 based on 2866 unique reflections. Most bond lengths and angles were normal. The Re≡O distance of 1.681(5) Å was longer than normal. It is postulated that this was caused by competitive π bonding between the deprotonated amidic nitrogen atom and the rhenium atom, as shown by the short Re—N distance (1.997(6) Å) compared to the equivalent distance for the amine nitrogen atom (Re—N, 2.151(4) Å). Key words: N2S2 ligands, rhenium, crystal structure.

Influence of the configuration of the amine nitrogen atom on the efficiency of fluorescence of 4-aminonaphthalimide derivatives

2004 ◽  
Vol 74 (11) ◽  
pp. 1728-1733 ◽  
Author(s):  
Yu. A. Mednykh ◽  
Yu. A. Manaev ◽  
V. V. Volchkov ◽  
B. M. Uzhinov
Keyword(s):  
Nitrogen Atom ◽  
Amine Nitrogen Atom ◽  
Amine Nitrogen

scholarly journals N-Tris[(2-aminoethyl)-2-(diphenylphosphoryl) acetamide)] — novel CMPO tripodand: synthesis, extraction studies and luminescent properties of lanthanide complexes

2012 ◽  
Vol 10 (1) ◽  
pp. 146-156 ◽  
Author(s):  
Elena Sharova ◽  
Oleg Artyushin ◽  
Alexander Turanov ◽  
Vasilii Karandashev ◽  
Svetlana Meshkova ◽  
...  
Keyword(s):  
Nitrogen Atom ◽  
Luminescent Properties ◽  
Lanthanide Ions ◽  
Acid Solutions ◽  
Acidic Media ◽  
Amine Nitrogen Atom ◽  
Europium Complexes ◽  
Amine Nitrogen ◽  
Anionic Complexes ◽  
Extraction Properties

AbstractA ligand system containing three carbamoylmethylphosphine oxide (CMPO) moieties attached to a tripodal platform with a central nitrogen atom has been synthesized for metal complexation and extraction from neutral and nitric acid solutions. Liquid-liquid extractions performed for Ln(III), both from neutral and acidic media, show excellent extraction properties which exceeded those for the known mono- and di-CMPO derivatives as well as the related tripodands. A considerable enhancement of the DLn values was observed in the presence of IL ([bmim][Tf2N]) in the organic phase towards lanthanide ions from 3M HNO3 solutions. The protonation of the central amine nitrogen atom of the ligand 1 in the acidic media provides also the effective extraction of the perrhenate anionic complexes. The europium complexes formed by mono- and tris-CMPO ligands in the solid state, as well as Eu(III) and Tb(III) complexes generated in solutions, possess intensive luminescence at 300K

The Tertiary Amine Nitrogen Atom of Piperazine Sulfonamides as a Novel Determinant of Potent and Selective β3-Adrenoceptor Agonists

ChemMedChem ◽  
2009 ◽  
Vol 4 (12) ◽  
pp. 2080-2097 ◽  
Author(s):  
Maria Grazia Perrone ◽  
Laura Bleve ◽  
Ernesto Santandrea ◽  
Paola Vitale ◽  
Mauro Niso ◽  
...  
Keyword(s):  
Nitrogen Atom ◽  
Tertiary Amine ◽  
Amine Nitrogen Atom ◽  
Amine Nitrogen ◽  
Adrenoceptor Agonists

scholarly journals Pyridine-4-carboxamidoxime N-oxide

IUCrData ◽  
2020 ◽  
Vol 5 (10) ◽  
Author(s):  
Clifford W. Padgett ◽  
Kirkland Sheriff ◽  
Will E. Lynch
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Nitrogen Atom ◽  
Hydrogen Bonds ◽  
Oxygen Atom ◽  
Metal Organic Frameworks ◽  
Amine Nitrogen Atom ◽  
Amine Nitrogen ◽  
Compound C ◽  
Metal Organic

Our work in the area of synthesis of metal–organic frameworks (MOFs) based on organic N-oxides led to the crystallization of pyridine-4-carboxamidoxime N-oxide. Herein we report the first crystal structure of the title compound, C6H7N3O2 [systematic name: (Z)-4-(N′-hydroxycarbamimidoyl)pyridine N-oxide]. The hydroxycarbamimidoyl group is essentially coplanar with the aromatic ring, r.m.s.d. = 0.112 Å. The compound crystallizes in hydrogen-bonding layers built from the formation of strong O—H...O hydrogen bonds between the oxime oxygen atom and the oxygen atom of the N-oxide, and the formation of N—H...O hydrogen bonds between one amine nitrogen atom and the N-oxide oxygen atom. These combined build R 3 4(24) ring motifs in the crystal. The crystal structure has no π–π interactions.

Structure–activity studies of β-carbolines. 3. Crystal and molecular structures of methyl β-carboline-3-carboxylate

1985 ◽  
Vol 63 (10) ◽  
pp. 2752-2756 ◽  
Author(s):  
Alastair K. S. Muir ◽  
Penelope W. Codding
Keyword(s):  
Nitrogen Atom ◽  
Biological Response ◽  
Benzodiazepine Receptor ◽  
Carbonyl Oxygen ◽  
Molecular Structures ◽  
Side Chain ◽  
Amine Nitrogen Atom ◽  
Amine Nitrogen ◽  
Crystal And Molecular Structures ◽  
Affinity Ligand

The crystal and molecular structures of methyl β-carboline-3-carboxylate, C13H10N2O, a high-affinity ligand for the benzodiazepine receptor, are reported. This candidate for the endogenous ligand for the receptor produces a biological response that is opposite to the anxiety-reducing effect of the usual agonists of the receptor and is, therefore, classified as an inverse-agonist. The space group is P21/c with a = 11.4866(9), b = 5.8091(3), c = 32.417(3) Å, β = 97.111(3)°, Z = 8. In both of the unique molecules, the ester side chain has an extended conformation and is coplanar with the β-carboline moiety. The carbonyl oxygen atom and the aromatic nitrogen atom are cis and form a three-centre hydrogen bond to the amine nitrogen atom of the other molecule in the asymmetric unit.

scholarly journals Synthesis and crystal structures of three Schiff bases derived from 3-formylacetylacetone and o-, m- and p-aminobenzoic acid

2022 ◽  
Vol 78 (1) ◽  
Author(s):  
Jan Henrik Halz ◽  
Andreas Hentsch ◽  
Christoph Wagner ◽  
Kurt Merzweiler
Keyword(s):  
Hydrogen Bonding ◽  
Nitrogen Atom ◽  
Crystal Structures ◽  
Schiff Bases ◽  
Molecular Fragment ◽  
Supramolecular Structures ◽  
Hydrogen Bridge ◽  
Aminobenzoic Acid ◽  
Aminobenzoic Acids ◽  
Hydrogen Bonding Networks

Treatment of 3-formylacetylacetone with the isomeric o-, m- and p-aminobenzoic acids led to the formation of the corresponding Schiff bases, namely, 3-[(2-carboxyphenylamino)methylidene]pentane-2,4-dione, 1, 3-[(3-carboxyphenylamino)methylidene]pentane-2,4-dione, 2, and 3-[(4-carboxyphenylamino)methylidene]pentane-2,4-dione, 3, all C13H13NO4, that contain a planar amino-methylene-pentane-2,4-dione core with a strong intramolecular N—H...O hydrogen bridge. The carboxyphenyl groups attached to the nitrogen atom are almost coplanar to the central molecular fragment. Depending on the position of the carboxyl unit, different supramolecular structures with hydrogen-bonding networks are formed in the three title structures.

scholarly journals Guest-Host Inclusion Complex Formation of 2-, 3-, and 4-Aminobenzoic Acids with Native and Modified Cyclodextrins

2016 ◽  
Vol 69 ◽  
pp. 10-21 ◽  
Author(s):  
Narayanasamy Rajendiran ◽  
J. Thulasidhasan ◽  
M. Jude Jenita
Keyword(s):  
Inclusion Complex ◽  
Inclusion Complexation ◽  
Aminobenzoic Acid ◽  
Time Resolved ◽  
H Nmr ◽  
Buffer Solutions ◽  
Aminobenzoic Acids ◽  
Modified Cyclodextrins ◽  
Ft Ir ◽  
Uv Visible

The inclusion complexation of 2-aminobenzoic acid (2ABA), 3-aminobenzoic acid (3ABA), and 4-aminobenzoic acid (4ABA) with α-cyclodextrin (α-CD), β-cyclodextrin (β-CD), hydroxypropyl-α-cyclodextrin (HP-α-CD) and hydroxypropyl-β-cyclodextrin (HP-β-CD) were studied in buffer solutions of differentpHs (pH~1 andpH~7) and it was carried out using UV-Visible, steady-state and time-resolved fluorescence. Dual fluorescence was observed for all the compounds in aqueous and CD medium. All the ABAs forms 1:1 inclusion complex at pH ~ 1 solution and mixture of 1:1 and 1:2 inclusion complex at pH ~7. With CDs, dual luminescence appeared at pH ~ 1 indicates, both NH3+and COOH groups are present in the interior of the CDs cavities. FT-IR,1H NMR, results suggest ABAs formed a stable inclusion complex with the CDs.

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